Electrochemical Dissolution of Ta and TaN Diffusion Barrier Materials

Electrochemical dissolution of both Ta and TaN into HF is demonstrated by cyclic voltammetry. For Ta dissolution, current maxima typical of passive film formation are seen, and the peak current occurs at about vs a saturated calomel electrode (SCE), while that for TaN dissolution occurs at about SCE. This report of electrochemical Ta and TaN dissolution demonstrates the possibility of all-electrochemical, noncontact methods for removal of Cu diffusion barrier materials. Four-point probe measurements demonstrate that the removal rates of Ta and TaN can be varied within the range of through the appropriate choice of potential.